/**
* Inserts the given node z before the given node v. And error occurs if v is the header
*
* @param v
* @param z
* @throws IllegalArgumentException
*/
public void addBefore(DLNode<E> v, DLNode<E> z) throws IllegalArgumentException {
DLNode<E> u = getPrev(v); // may throw an IllegalArgumentException
z.setPrev(u);
z.setNext(v);
v.setPrev(z);
u.setNext(z);
self.size++;
}
/**
* Inserts the given node z after the given node v. And error occurs if v is the trailer
*
* @param v
* @param z
* @throws IllegalArgumentException
*/
public void addAfter(DLNode<E> v, DLNode<E> z) throws IllegalArgumentException {
DLNode<E> w = getNext(v); // may throw an IllegalArgumentException
z.setPrev(v);
z.setNext(w);
w.setPrev(z);
v.setNext(z);
self.size++;
}
/**
* Returns a string representation of the list
*
* @return s string representation of the list
*/
@Override
public String toString() {
String s = "[ ";
DLNode<E> v = self.header.getNext();
while (v != self.trailer) {
s += v.getElement();
v = v.getNext();
if (v != self.trailer) {
s += ", ";
}
}
s += " ]";
return s;
}
/**
* Removes the given node v from the list. An error occurs if v is the header or tailer
*
* @param v
*/
public void remove(DLNode<E> v) {
DLNode<E> u = self.getPrev(v); // may throw an IllegalArgumentException
DLNode<E> w = self.getNext(v); // may throw an IllegalArgumentException
// unlink the node from the list
w.setPrev(u);
u.setNext(w);
v.setPrev(null);
v.setNext(null);
self.size--;
}
/**
* Returns the node after the given node v. An error occurs if v is the trailer
*
* @param v the current node we are looking to get the next node of
*/
public DLNode<E> getNext(DLNode<E> v) throws IllegalArgumentException {
if (v == self.trailer) {
throw new IllegalArgumentException("Cannot move forward past the trailer of the list");
}
return v.getNext();
}
/**
* Returns the node before the given node v. An error occurs if v is the header
*
* @param v the current node we are looking to get the previous node of
*/
public DLNode<E> getPrev(DLNode<E> v) throws IllegalArgumentException {
if (v == self.header) {
throw new IllegalArgumentException("Cannot move back past the header of the list");
}
return v.getPrev();
}